The development of nanoparticles (NPs) covered with organic functional groups has recently excited considerable interest in liquid crystal (LC) nanoscience. Research over the past few years has shown that the presence of NPs dispersed into low molecular mass thermotropic LCs can bring about striking changes to the optical and electro-optic behaviour of LC systems. For example, it has been demonstrated that doping nematic LCs with nanoscale MgO can result in lower operating voltages and shorter response times. Gold nanoparticles in particular have been shown to allow electrically controlled light-scattering when embedded in a nematic LC, allowing for voltage-dependent colour tuning.
In addition, liquid crystalline phases having one or two-dimensional long range orientational ordering also present an excellent choice for the synthesis as well as assembly of NPs into larger, organized structures (arrays) with the added benefit of fluidity imparted by the LC. Hence, the final self-assembled superstructure can be manipulated by external stimuli, a quality not shared by many products of other assembling methods using polymers or surfaces (interfaces) leading to more confined NP arrays.
Thus far, the majority of studies have concentrated on lyotropic liquid crystalline systems as templates or matrices for the patterning of NPs. In addition, most studies involving the effect of NPs on the LC host itself have focused on conventional rod-like LCs.
We have extended such studies to the class of thermotropic liquid crystalline compounds which have come to be known as bent-core or “banana-shaped” LCs. Bent-core compounds exhibit unique properties (for example, high polarization values and second-order susceptability coefficients) which recommend them for use in pyroelectric or piezoelectric applications in non-linear optical (NLO) devices or in dispersive devices similar to polymer-dispersed liquid crystals (PDLCs).